From London in 1915 to Gaza in 2009, the aerial bombing of cities has been a central feature of modern industrialised warfare. Gabriel Moshenska of University College London has been studying the drive to build air-raid shelters in 1930s Britain. He finds that the grim experience of the Spanish Civil War was a dominant influence.

Alongside St Paul’s Cathedral, Winston Churchill, evacuees, and ga

s masks, civilian air-raid shelters are amongst the most familiar images of the Second World War in Britain. In the art and literature of the Home Front, the air-raid shelter and its inhabitants – frightened, dazed, defiant – feature prominently. Bill Brandt’s photographs of Londoners crowded on the platforms of underground stations are echoed in Henry Moore’s sketches and the novels of Elizabeth Bowen, Graham Greene, and others.

The Anderson shelter and the crowded underground-station platform are icons of British Civil Defence. But those images of shelters and shelterers represent a thread connecting civilians caught up in conflicts across time and space from First World War London to Civil War Barcelona, Second World War Tokyo and Hamburg, and on to Hanoi, Beirut, Baghdad, and Gaza.

The First World War

The first bombs fell from an aircraft in 1911, when the Italian military bombarded Ottoman troops in Libya with hand grenades during the Italian-Turkish war of 1911-1912. Four years’ later, the Zeppelins of the German Army and Navy were targeting British cities with bombs weighing up to half a ton.

At the outbreak of the First World War, virtually all combatant nations possessed military aircraft. By the armistice four years later, a distinctive category of bomber aircraft had emerged, including the Russian Ilya Murometz, the Italian Caproni, the French Breguet 14, the German Gotha and Giant, and the British Handley-Page. By the end of the war, bombs had fallen on Antwerp, London, Felixstowe, Ludwigshafen, Constantinople, and many other European cities.

The British public’s very reasonable response to the growing number and severity of air raids from 1915 onwards was to take shelter. The scientist J B S Haldane reported that in London as many as 300,000 went into underground stations, while another 500,000 slept in cellars and basements. Railway viaducts such as the Tilbury Arches in Stepney were also popular refuges, although the protection offered is doubtful. In Ramsgate, caves and tunnels in the chalk cliffs were employed as shelters for several thousand people. All such shelters would be reused in the Second World War.

The oldest surviving air-raid shelter in Britain is a little grey garage behind a house in Cleethorpes, Lincolnshire. After Zeppelin attacks killed a number of residents and soldiers in April 1916, Joseph Forrester, a chemist and local councillor, constructed a reinforced concrete air-raid shelter with walls half a metre thick. The structure is 4m wide and 5m deep, and consists of a single room with two entrance lobbies. At some point, it was turned into a garage, and as such it survives as a strikingly modern-looking remnant of the first strategic bombing campaign in history.

Barcelona during the Spanish Civil War

It was in the Spanish Civil War of 1936-1939 that the spectre of bombing in Europe grew from a fear into a real threat. The bombing of Guernica and other towns by the German air force raised the possibility of total urban destruction. Italian raids on Barcelona saw a modern, cosmopolitan European city come under attack for the first time since 1918. It was also in Barcelona that the first purpose-built deep bomb-proof shelters were constructed for use by the civilian population.

Following the Fascist military coup and the outbreak of the Civil War in 1936, Barcelona become one of the main strongholds of the Republican Government. When the army garrison attempted to impose military rule, it was defeated in combat by the local anarchist militias. From late 1937, Barcelona functioned as the Republican capital.

The city was bombed heavily during the war, beginning with bombardment from the sea by an Italian cruiser in February 1937. A total of 194 bombing attacks were made on Barcelona, the majority by the Italian air force from its base in Majorca. Around 1,500 buildings were destroyed and 2,500 people killed.

In response, in 1936, the Government of Barcelona formed the Anti-Aircraft Passive Defence Department to coordinate the provision of air-raid protection. Shelter building began immediately, with the aim of cutting 25 tunnel shelters into the bedrock. Following the first bombings, a booklet was produced with instructions for building your own shelter, and various community groups and residents’ associations began to dig shelters around the city. In addition to the 30 shelters eventually built by the city authorities, more than 1,300 shelters of assorted sizes and shapes were built by the general population.

These shelters were cut into the soft sandstone bedrock beneath city squares, empty lots, or under streets. Most were built as networks of tunnels with arched roofs lined with elaborate brickwork, in the local Catalan style. The shelters were fitted with benches, and most had toilets, a dispensary, and electric lighting run off the mains or rechargeable batteries.

Use of the shelters was not universally popular. Some found them unpleasant or claustrophobic, and there were widespread doubts as to their effectiveness. Through 1938, the numbers using the shelters fell.

Because of the wide range of building methods, many of the shelters were not fully bomb-proof, and the introduction of new aircraft and larger bombs by the Italian and German air forces increased the danger.

The bombing continued until Barcelona fell to the Fascists in January 1939. Following the occupation, many air-raid shelters were enlarged and reinforced, as Fascist leader Franco feared that the Second World War might spread into Spain. In the event, this did not happen, and the air-raid shelters of Barcelona were sealed up and forgotten or turned to other uses.

The lessons of Spain

The civil defence of Barcelona was watched keenly across Europe. The scientist J B S Haldane visited Barcelona a number of times during the Civil War and observed the construction of shelters in the city. His book ARP, published by the Left Book Club in 1938, attempted to bring the lessons of Barcelona to the attention of the British public and politicians. Haldane describes a visit to a shelter under construction in Barcelona:

There were four entrances which led down by ramps with a few steps to the tunnels. The ramps twisted repeatedly, until a depth of about 55 feet below the ground was reached. Here began a labyrinth of passages about 7 feet high by 4 feet broad. They were cut in the very tough soil of the district, and had no lining, and I think no supports such as pit props. They were, however, being lined with tiles with a cement backing so at to give a semicircular arch and vertical walls.

Haldane noted the low cost of the shelters and the use of volunteer labour in their construction. He also described other shelters in the city, including an experimental model using two concrete roofs separated by an air space to absorb blast.

A number of British civil engineers travelled to Spain to study the effects of bombing on cities. Francis Skinner worked with Haldane on the brick-lined tunnels described above, while Cyril Helsby visited Barcelona on a trip sponsored by the Labour Party. His study of bomb damage on residential buildings in Barcelona includes a number of detailed plans of surface shelters and shallow, semi-sunken shelters.

Like Haldane, Helsby returned to Britain with a great admiration for the level of protection provided by the Barcelona shelters, especially compared to the meagre British provision at the time. Helsby’s research was presented to the Institution of Structural Engineers, and was debated by a number of prominent scientists and politicians, many of whom were persuaded of the need to become ‘Barcelona-minded’.

Helsby’s work influenced the Labour Party, but, like Haldane’s work and also reports by distinguished engineers such as Ove Arup, it was rejected by the official Hailey Report on air-raid protection. By the outbreak of the Second World War, many of the hard-earned lessons of Barcelona were being acted on in Britain – but not all.

The Second World War

The most common and well-known British air-raid shelter of the Second World War is the Anderson shelter. By the start of 1939, more than a million of these part-sunken shelters, named after the politician responsible for ARP, had been installed in private gardens. Built of curved sheets of steel, they held four to six people each, and were given free to low-income families. By the time the Blitz began in earnest, more than 2.25 million families had Anderson shelters in their gardens.

The Andersons, however, were cold, damp, and frequently flooded. Many people preferred the communal shelters that began to be built in parks, on pavements, and at other open public spaces. The result was a great variety of forms, capacities, locations, and levels of protection. Broadly, four main types can be identified: surface, semi-sunken, sunken, and deep.

Surface shelters

Surface shelters were often simply long brick-and-concrete structures built on pavements or beside buildings. They had one or two entrances, and offered shelter from collapsing buildings and shrapnel. Some could hold several hundred people in varying levels of comfort. They were not particularly blast-proof, however, as many models were badly constructed, often using sub-standard mortar, and were liable to collapse. Other surface shelters were constructed from prefabricated reinforced-concrete units, and a few more bunker-like ones were cast in situ using shuttering.

The Civil Defence Act 1939 declared that: ‘To lessen the number of casualties from a direct hit, the unit size of shelters should preferably be limited to parties of not more than 50 persons’. From then on, this became the common size for surface and semi-sunken air-raid shelters in schools, businesses, and public areas. Most were formed from pre-cast concrete panels or segments, and could be built to a number of sizes and specifications.

Semi-sunken shelters

Semi-sunken shelters such as the Anderson used shallow initial excavation combined with earth banking to increase the strength and blast-resistance of the structure. One of the most common semi-sunken shelters used preformed segments with a curved roof, which could be more easily buried.

As with surface shelters, semi-sunken shelters tended to have their entrances at an angle or behind a wall to protect the occupants from blast, while lowering the risk of being trapped behind a blocked doorway. However, as Helsby had noted in Barcelona, ‘Before they had actual experience of air raid, the people of Barcelona imagined that open trenches or lightly covered shelters would be proof against bombing. They have learnt better now.’ Once again, the hard-earned lessons of Barcelona were squandered by British policy-makers.

Sunken shelters

Sunken shelters often started out as basements or trenches. Basements and cellars were reinforced with planks and girders at various angles so that they could withstand the collapse of the building above. Trenches were dug on open pieces of land and reinforced with sandbags, sheet metal, and wooden props. These were intended both as shelters from bombing or strafing and subsequently to prevent gliders from landing. Later on, many of these trenches were built up with steel, concrete panels, or cast concrete, to create more stable and better protected shelters that could survive bombs exploding underground close by, as well as providing more comfortable accommodation.

Deep shelters

None of the shelters described above was capable of surviving a direct hit. Rather, they were designed to protect against the statistically far higher possibility of a near miss, with its risk of flying bomb fragments and collapsing debris. In the pre-war period, however, there was a widespread campaign for the construction of deep underground shelters that could survive direct hits from heavy bombs.

Following media reports of shelters in Barcelona, many people regarded the government’s air-raid precautions as woefully, even criminally, inadequate, particularly in regard to large, densely-populated urban areas. The Communist Party conducted a spirited campaign in favour of deep shelters for the working class districts around industrial centres likely to be targeted by the bombers.

Finsbury Borough Council commissioned the civil engineer Ove Arup to study the effects of bombing on soil and buried structures, and to design a range of giant bomb-proof shelters. Arup’s designs are bizarre and beautiful, resembling complex molecules, giant spirals, honeycombs, and enormous subterranean multi-storey car-parks. The smallest held 50 people, but the largest was designed to hold 12,300 in bomb-proof safety below many metres of earth and reinforced concrete.

In the event, few of the giant deep shelters were constructed, and none for civilian purposes. Instead, the public began to use the underground stations in London as unofficial shelters. Unlike Andersons and communal shelters, the tube was dry, warm, and apparently bomb-proof. While the authorities initially banned the use of the tube in fear of transport disruption, they soon relented in the face of massive public demand. Not all tube stations were sufficiently deep, however, and bombings at Balham and Bank killed several hundred people.

Remembering everyday life in the shelters

Today, many of the wartime generation can remember their experiences of different types of shelter: the damp and cramped Anderson, the bleak and unhygienic public shelters, and the novelty of school shelters where shrapnel, gossip, and exam answers could be surreptitiously exchanged. Many also recall the attempts by parents and teachers to make shelters into a more familiar, domestic space, with amenities, decorations, and stoves for brewing tea.

The history of air raid shelters in pre-war and wartime Britain is a gripping story of engineering genius and political short-sightedness, and also a story about the men, women, and children who inhabited and endured them.